More Firm Data On Warming
The northern hemisphere is hotter now than at any time in the past 1500 years, according to the most comprehensive reconstruction of the earth’s temperature over the last two millenniums.
It’s likely the southern hemisphere is also warmer than ever although data is sketchier, claim US and British scientists.
The new findings come from a team led by Michael E. Mann, director of the Environmental Systems Institute at Pennsylvania State University in University Park. In an article in the US journal Proceedings of the National Academy of Sciences, they reported that they’d pulled together the largest ever set of climate data, enabling them to assess changes on decadal and centennial scales.
Associate Professor Mann and his colleagues used “natural climate archives” like tree-rings, corals and ice cores, along with historical documentary records and recently updated instrumental data to reconstruct the climate of past centuries in unprecedented detail and compare it with existing conditions.
“Our results extend previous conclusions that recent northern hemisphere surface temperature increases are likely anomalous in a long-term context,” they claimed.
While the new research also concluded that the so-called Medieval warmth from 950-1100 was hotter than previously thought, the last decade was hotter still.
“The findings deeply reinforce the incontrovertible conclusion that we are warming rapidly outside natural variability,” said climate scientist Andy Pitman, co-director of the Climate Change Research Centre at the University of NSW.
There is obviously a need to obtain more southern hemisphere data. That would help scientists further refine the climate change models used to predict future conditions in regions around the world.
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